Drill centralizers



Sept. A27, 1966 B. ZETTERGREN 3,275,388

DRILL CENTRALIZERS Filed March 18. 1965 2 Sheets-Sheet 1 INVENTOR.

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SePt- 27, 1966 B. ZETTERGREN 3,275,388

DRILL CENTRALIZERS Filed March 18, 1963 2 Sheets-Sheet 2 35 Ll a7 a s: VJ U Z 39"' as@ N /3 /6 42 Fig. 5

INVENTOR FMG-E2 ZEN-s Re :EH

KWG/2U a1 Amends-Y United States Patent() 3,275,388 DRILL CENTRALIZERS Birger Zettergreu, Nacka, Sweden, assigner to Atlas .Copco Aktiebolag, Nacka, Sweden, a corporation .of Sweden V.Filed Mar. 18,1963, Ser. No. 265,829 Claims priority, application Sweden, Mar. 29, `1962, 3,512 9 Claims. (Cl. 30S-3.9)

This invention relates to drill centralizers and particu- :lai- 1y 'to drill centralizers of the type having a pair of .guiding arms swingable about pivots on a base between active and inactive positions. In drill centralizers of this type 1t sometimes can happen that the guiding arms during operation unintentionally leave inactive position and cause damages by contacting movable parts. By that reason the guiding arms have often been arranged lockable in inactive position. Hitherto known lockable drill centraliz- .ers,l however, are usually found to be comparatively complicated and do not -provide easy synchronization and simultaneous movement of the guiding arms Ito their .different positions as would be desirable.

It is a main object of the invention `to provide a drill Vcentralizer of the above type in which the guiding arms are retained inactive as well as inactive positions by means ,of asole simple spring means. A further impor- -tantobject is to provide a drill centralizer 'of the above type in which the movement of the guiding arms is reffectively synchronized making it possible to move both guiding Aarms simultaneously to active or inactive posi- -tions by asingle movement of ones hand.

The invention will be described more in detail `by the .aid of the enclosed drawing. Therein FIG. 1 lshows a .centralizer in FIG. 2. FIG. 7, nally, shows a modied embodiment in a view corresponding to FIG. 4.

The drill centr-alizer shown in the figures consists of a base 10 which is .provided with plane holed connecting surfaces 11 intended to be attached by means of `bolts to .the forward end of a feed bar, not shown. The feed bar supports in known manner `a rock drilling machine slidable thereon as well as a drill steel and appurtenant feeding devices. The base 10 is provided with three -bosses 12 into which are screwed long parallel bolts 13, which on one hand penetrate a front plate 15 and on the other traverse spacing tubes 16 lying between the front plate 15 and the bosses 12. By tightening the bolts 13 the front plate 15 and the spacing tubes 16 are connected to form a unity with the ibase I0. For securing the bolts 13 against being shaken loose, a locking plate 17 may be laid underneath the 'bolt heads and 4rnay be provided with upturned locking portions '18.

The two upper spacing tubes 16 form pivots for guiding arms V19.and 20 which project in upward direction from the base 10 and at their upper ends form 'semicylindrical guides 21 for the drill steel, not shown. In order that the guides 21 in active position shall provide a distinct centering position coaxially relative to the 3,275,388 Patented Sept. 27, 1966 ice Vnalled between the ears 24. On the outer end of the locking arm 26 a washer A28 is Xed by means of a locking pin l27. Against'the washer there is supported a helical spring 29 arranged around the locking arm which spring bears against the'inside of a handle sleeve 30 slidably arranged onethe locking arm. The handle sleeve 30 carries at its outer end ahandle 31 while its inner end is tapered conieally at 32. 'IThe locking arm 26 is intended for entering between upwardly turned ears 33 on the guiding `arm 19 and the conieally pointed portion 32 fof the handle sleeve 30 coacts with conical recesses 34, FIG. 1, in the ears 33. By pulling the handle 31 and turning of the locking arm 26 onthe journals of the pivot '25 the 'locking arm may be vibrought down between the ears 33 with the spring 29 compressed. If the handle is released in this position the conieally pointed portion 32 of the handle :sleeve 30 enters the recesses 34 and locks the guiding arms 19, 20 in active position.

The guiding arms 19, 20 are double-armed or bell crank llevers carrying a pair of arms 35, T36 opposed to the guides 21 and pointing in the direction of each other. The arm 35 is provided with a pair of parallel bores 37 extending radially inward Vtowards-the vspacing tube 16. In each of the bores 37 there is inserted a helical spring 38 under Vprecompression -between the spacing tube 16 and a substantially semi-cylindrical journalbody 39 eX- tending in parallel relation to the spacing tubes 16. The journal body 39 is provided with recesses-40 arranged coaxially with the bores 37 for receiving one end of the helical springs 38 and from the journal body 39 there projects a pair of spring guiding pins -41 into t-he springs 38 and the bores 37. The journal body 39 is pivotally journalled in a semi-cylindrical recess 42 formed in the end of the arm 36 of the guiding arm 20.

The front plate 15 is at its upper portion provided with a rearwardly directed portion 43 forming a downwardly turned yplane abutment 44. The Aarm 36 on the guiding arm 20 is provided with an abutment 45 intended for cooperation with the abutment 44.

When the drill centralizer lis Ato vbe placed from the active position illustrated in FIG. 3 into inactive position according to FIG. 4, the operator, standing for example at Vthe side of the drill .centralizer opposite to the handle 3l, seizes the handle V31 and pushes the handle sleeve 30 Y forwardlyin order to disengage its conieally pointed portion 32 from the recesses 34 in the ears 33 on the arm 19. Thereupon the locking arm A26 ,is turned by the handle 31 on the journals of the pivot `25 about 180 degrees, whereupon the operator by pulling the handle farther -away tromthe drill steel turns the guiding arm 20 around lits spacing tube 16 in clo'ckwisedirectilon in FIG. 3. The 'turning movementfis transmitted by the arm 36 and its cylindrical recess 24 to the journal body 39, which is urged to follow the arm 36 while compressing the springs 38. The spring Aguiding pins 41 of the journal body 39 during the ycourse of this produce coupled swinging of the arm 35 andthe guiding arm 19 laround its spacing tube 16 counterclockwise in FIG. 3, whereby full synchronization of the movement of both guiding arms 20,

19 is effected. During swinging of the guiding arm 20 the arms 3S, y36 pass the central horizontal plane through In said i Return of the guiding arms 19,/20', to active position is performed simply by pushing and` displacing Yof the arm 20, FIG. 4, in the direction of the drill steel. After an initial compression the springs 38 again pass their snap-over point position, whereupon they under the expansion will cooperate towards bringing both guiding arms 19, 20 simultaneously into active position for retaining them therein. Finally the locking arm 26 is turned by means ofthe handle 31 down between the ears 33 in a manner to bring the handle sleeve 30 inengagement with the locking recesses 34, thereby positively interlocking the guiding arms 19, 20.

As an alternative the spring means 38, 39 in FIG. 4 may, as shown in FIG. 7, be exchanged for a massive, for example prismatic rubber block 46 inserted and xed under axial precompression in corresponding alignedy apertures 47 in thearms 35,36 turned inwardly in the direction lof each other. Operation of this arrangement is fully identical with operation of the embodiment in FIGS. 1-6.

The embodiments of the invention described above and shown in the drawing should only be considered as examples and the invention may be modified in many further ways within the scope of the claims following hereinafter.

What I claim is:

1.'In drill steel centralizer apparatus of the character described for guiding the drill Vsteel of a rock drilling machine and having a base for attachment to said machine and a pairvof opposed guiding arms having pivotal connections to said base and being Vmovable toward and away from each other from a guiding position adjacent each other to a non-guiding position away from eachV other, and a guiding surface disposed on each of said arms for mutual cooperationto forma guiding opening in said guiding position of said arms, the combination which comprises a second pair of arms rigidly disposed on t said guiding arms and extending radially from said pivotal connections therefor on the ends thereof `opposite said guiding surfaces, said second arms extending toward each other in opposed relationship, axially compressible resilient means disposed under compression between said second arms, pivot means on one of said second arms forV connecting lone end of said resilient means pivotally to said arm, means on the other of said second arms for connecting the other end of said resilient means slide-ably to saidlarm for guided axial movement of said resilient means with respect to said arm while being angularly rigid relative thereto, and means in said resilient `means pro-y viding substantial Vlater-al rigidity thereof whereby'said kresilient means has a snap-over point in an intermediate i 1 in which said guiding arms and said second arms thereon are bell crank levers having a longer. and a shortery arm extending from the pivotal connections therefor withl 3. Drill steel centralizer apparatus as recited in claim the long arm forming the guiding arm thereof andthe shorter arms disposed in opposed relationship to each other with said resilient means compressed and interposed between said short second arms.

4. In drillsteel centralizer apparatus of the character .described `for guiding the drill steel of a rock drilling machine and having a base with a pair of bell crank levers pivotally disposed thereon, said bell crank levers having a long arm and a short arm with said pair of long arms movable from a guiding position adjacent each other to a non-guiding position away from each other and said short arms extending in opposed relationship to` each other, the combination which comprises a guidingsurface disposed on each of said'long arms for cooperating with Y each other to form a guiding opening in the guiding position of said long arms, a spring between said short arms and connected thereto whereby movement of one lever brings about synchronized movement of the other lever,

by having a snap-over point in said spring `in an interi mediate position of swing of said levers for snapping said long arms into guiding position at one side of said snapover point and into non-guiding position at the other side thereof, and a rigid spring lguide disposed 'in said 1 in which a pair of pivots are disposed on said base for connecting said guiding arms and in which said pivots are be guided.

spring for providing` the connectionbetween said short arms and for Vsynchronizing the movement of said levers. 5.`Dril1 steel centralizer apparatus as recitedin claim 4 in which an abutment' is disposed on :said base for` limiting the movement of said short arms in the nonguiding position thereof..

6. Drill steel centralizer apparatus of the character described having arbase with a pair of guiding arms pivotally disposed Ithereonand cooperating guiding ends on said guiding arms, said guiding arms being bell crank levers and .pivotable on said base from a guiding position with said guiding ends adjacent each other to a non-guiding position with said guiding ends away fromeach other and with arms on said `levers at the ends thereof opposite said guiding ends disposed in opposed relation to each` other, the combination which comprises a resilient member in engagement with and disposed between said last` mentioned arms, said resilient member having a snap-over position in an intermediate position of swing of said guiding arms for snapping said guiding arms into guiding position at one side `of said snap-over point and into nonguiding position at the other side thereof and for retaining said guiding arms in the selected positions thereof.

7.'Apparatus vas recited in claim 6 in which said guiding arms are substantially equal in form and are, pivotally mounted `on said base in opposed relation lto each-other. 8. A drill steel centralizer apparatus of the character describe-d for guiding a drill steel of a rock drill and having a base, a pair of guiding arms pivotally disposed on said` base, opposed cooperating guiding ends on said,

guiding arms with said guiding arms being bell crank levers substantially equal in form and mounted in'op-i posed relationship Vto swing ou said base from aguiding guiding position at the other side thereof` and for retain-` ing -said guiding arms in the selected positions thereof, with said rubber body having suiiicient rigidity'toV move Vone of said arms past the intermediate position `in resaid bell crank levers for locking said guiding arms in 5 the guiding position thereof.

References Cited bythe Examiner UNITED STATES PATENTS 3/ 1891 Turner 200-67 9/1919 Newton 200-67 Farrell 30S-3.9 Curtis 308-39 Bower 200-67 Curtis 30S- 3.9

DAVID I. WILLIAMOWSKY, Primary Examiner. ROBERT C. RIORDON, FRANK SUSKO, DON A.

WAITE, Examiners.

10 L. L. I OI-DI SON, Assistant Examiner. 

1. IN DRILL STEEL CENTRALIZER APPARATUS OF THE CHARACTER DESCRIBED FOR GUIDING THE DRILL STEEL OF A ROCK DRILLING MACHINE AND HAVING A BASE FOR ATTACHMENT TO SAID MACHINE AND A PAIR OF OPPOSED GUIDING ARMS HAVING PIVOTAL CONNECTIONS TO SAID BASE AND BEING MOVABLE TOWARD AND AWAY FROM EACH OTHER FROM A GUIDING POSITION ADJACENT EACH OTHER TO A NON-GUIDING POSITION AWAY FROM EACH OTHER, AND A GUIDING SURFACE DISPOSED ON EACH OF SAID ARMS FOR MUTUAL COOPERATION TO FORM A GUIDING OPENING IN SAID GUIDING POSITION OF SAID ARMS, THE COMBINATION WHICH COMPRISES A SECOND PAIR OF ARMS RIGIDLY DISPOSED ON SAID GUIDING ARMS AND EXTENDING RADIALLY FROM SAID PIVOTAL CONNECTIONS THEREFOR ON THE ENDS THEREOF OPPOSITE SAID GUIDING SURFACES, SAID SECOND ARMS EXTENDING TOWARD EACH OTHER IN OPPOSED RELATIONSHIP, AXIALLY COMPRESSIBLE RESILIENT MEANS DISPOSED UNDER COMPRESSION BETWEEN SAID SECOND ARMS, PIVOT MEANS ON ONE OF SAID SECOND ARMS FOR CONNECTING ONE END OF SAID RESILIENT MEANS PIVOTALLY TO SAID ARM, MEANS ON THE OTHER OF SAID SECOND ARMS FOR CONNECTING THE OTHER END OF SAID RESILIENT MEANS SLIDEABLY TO SAID ARM FOR GUIDED AXIAL MOVEMENT OF SAID RESILIENT MEANS WITH RESPECT TO SAID ARM WHILE BEING ANGULARLY RIGID RELATIVE THERETO, AND MEANS IN SAID RESILIENT MEANS PROVIDING SUBSTANTIAL LATERAL RIGIDITY THEREOF WHEREBY SAID RESILIENT MEANS HAS A SNAP-OVER POINT IN AN INTERMEDIATE POSITION OF SWING OF SAID GUIDING ARMS, SO THAT MOVEMENT OF ONE OF SAID GUIDING ARMS PAST SAID SNAP-OVER POINT CAUSES SAID RESILIENT MEANS TO MOVE THE OTHER SAID GUIDING ARM FOR SNAPPING SAID GUIDING ARMS INTO SAID GUIDING POSITION AT ONE SIDE OF SAID SNAP-OVER POINT AND INTO SAID NON-GUIDING POSITION AT THE OTHER SIDE THEREOF AND FOR HOLDING SAID GUIDING ARMS IN SAID SELECTED POSITIONS THEREOF. 